Nutrients In Chesapeake Bay

Image of Chesapeake Bay
To measure water quality and use authentic satellite data to explore the effects of nutrients in the Chesapeake Bay and the rivers of its watershed
Grade Level: 9 – 12
Estimated Time for Completing Activity: 4 hours field work, 50 minutes class work
Learning Outcomes:
  • Students will perform tests on the water quality of a river that drains into a larger estuary.
  • Students will use current satellite data to compare their results and explain how the area that they tested on the river affects the estuary as a whole.
  • Overview of Phytoplankton and Chlorophyll (See Lesson Links)
  • Field Trip to collect data to compare to satellite data
  • Familiarity with using the Internet to collect information
  • Computer with Internet Access
  • Secchi Disk (see Lesson Link)
  • pH Test Kit
Lesson Links:

The Chesapeake Bay is the largest estuary in the US. Eleven rivers empty into the bay creating the Chesapeake Bay Watershed. The watershed includes four major rivers: (1) the James, which flows through Richmond, Virginia, (2) the Potomac, which flows through Washington, D.C., (3) the Potabsco River, which flows through Baltimore, Maryland, and (4) the Susquehanna, which flows through many centers in Maryland and Pennsylvania.

From urban areas and cultivated fields in which wetlands were not preserved, runoff can run into the rivers unfiltered. This can cause an excess of nutrients to be introduced to the rivers. These nutrients can include nitrates and phosphates that come from fertilizers, untreated animal, and treated and untreated human waste. They can cause uncontrolled growth of an abundance of algae which can eventually increase the turbidity of the river, not allowing light to reach the bottom of the river. As algae grow it will remove CO2 from the water, a contributing factor in carbonic acid. As CO2 is removed from the water the pH will rise becoming more basic. Through studying pH trends it is possible to conclude that the change could be related to algae growth and or bloom. This could result in the loss of sub-aquatic vegetation (SAV) as well as the organisms which rely on it for food and habitat.

There are a variety of tests that can be conducted to determine the presence of algae in the rivers. Two of these tests include pH and turbidity. Turbidity can be measured using a Secchi disk in which we can determine how far into the water it is still visible. We can also study the effect of the algae in the rivers such as the Chesapeake Bay viewing the MY NASA DATA on chlorophyll-a in the Bay. These parameters can also be studied on a local level as a class project.


On the river, do the water quality testing as prescribed to determine the pH and turbidity of the river. See Lesson Links for protocols.

For the MY NASA Data portion of the lesson, follow these steps:

1.Click on the lesson link to the Live Access Server (Advanced Edition).
2.In the upper left hand corner, click on the "Data-set" button to choose a data parameters.
3.Click on Oceans and then select Concentration of Chlorophyll in Sea Water (SeaWiFS) and then close the data parameter choice menu.
4.Under the "Line Plot" Menu to the left side of the screen, click on "Time" to produce a Time Series (line) plot.
5.Using the compass input boxes input boxes below the navigation map in the upper left hand corner, enter 37.14 N in the top box, and 76.15 W in the bottom box, This will take you to a location within the mouth of the Chesapeake Bay. For this lesson, if there is another location that you wish to study, simply use a different latitude and Longitude and update your plot.
6.Using the drop-down menus, select the time range of July 1997 – July 2005. Be sure to update the plot using the "Update plot" button at the top left of the page to insure that all the changes have been made to the plot.
7.Print or save a copy of the graph so that you can have it to answer the questions at the end of the lesson.


1. By looking at your results from the river study and the LAS data, can you see a relationship between the amount of chlorophyll that is present in the bay and time of year? Explain your answer.

2. From the line plot, during which years or times of the year have the highest peaks? What could you conclude about the activities that occurred along the rivers at those times?

3. From our studies, what can you conclude about the relationship of our activities along the river and how they may affect the Chesapeake Bay?


1. Compare the results from the line plots with other parameters to see if there is a relationship between chlorophyll a and other factors such as sea temperature, wind speed and air quality.

2. Compare the chlorophyll a results with the Monthly Normalized Difference Vegetative Index (NDVI). Perhaps there is a relationship because NDVI on fertilized fields may contribute to nutrients entering the river.

Lesson plan contributed by Jim Evans, Washington, D.C.

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